This invention relates to an adhesive agent for mutual union of two oxide type ceramic articles and to a method for the manufacture of this adhesive agent.
Heretofore, mutual adhesion of two oxide type ceramic articles has been accomplished by adopting a method which comprises interposing a metal between the opposed surfaces of these ceramic articles and filling up the intervening gap with silver solder (Japanese Patent Publication Sho 47(1972)-21569) or a solder glass method, for example. The former method entails time-consuming and complicated work because it requires interposition of a metal. Besides, this method is not workable when the ceramic articles to be joined have complicated shapes. Since the latter method uses a solder which is preponderantly formed of glass, it has the disadvantage that the solder sustains breakage under thermal strain, offers insufficient thermal resistance, and suffers heavy degradation of its ability to resist chemicals because of the occurrence of an alkali upon vitrification.
For the union of ceramic articles in general including articles of oxide type ceramics, some of the present inventors participated in perfecting earlier inventions. One of these is the invention of U.S. Pat. No. 4,293,356 which concerns an adhesive agent formed of a mixture of CuS, LaCrO.sub.3, SiO.sub.2, and Cu. Two others are the inventions of U.S. Pat. No. 4,486,257, granted Dec. 4, 1984 and U.S. Pat. No. 4,447,283, granted May 8, 1984 which concern adhesive agents respectively formed preponderantly of calcium fluoride or a mixture of calcium fluoride with kaoline and of an alkali fluoride or a mixture of an alkali fluoride with kaoline. All these adhesive agents exhibit contact strengths of not more than about 100 kg/cm.sup.2. As the use found for ceramics is now expanding, ceramic articles are now required to be available in a wide variety of shapes. In the circumstance, the adhesive agents used for mutual adhesion of these ceramic articles are naturally expected to offer ample adhesive strength.
One object of this invention is to provide an adhesive agent capable of joining two oxide type ceramic articles with high adhesive strength.
Another object of this invention is to provide a method for joining two oxide type ceramic articles to each other with high adhesive strength.